Compressed air coupled chemical energy storage system and load shedding speed control method

Abstract

The present application relates to the technical field of load rejection overspeed control, and particularly relates to a compressed air coupled chemical energy storage system and a load rejection speed control method, which comprises a power generation module, which generates power through compressed air work; a power transmission module, which transmits the power generated by the power generation module to a power grid; and a load rejection module, which is disconnected from the power generation module under a load rejection condition, and the residual rotational inertia in the power generation module and the residual pressure gas caused by the closing delay of the intake electric main air valve cause the rotor speed to rise, and the load rejection module converts the residual kinetic energy into electrical energy for storage. In the present application, when the power generation process encounters a load rejection condition, the electrochemical energy storage device is charged through load transfer, so that during and after the closing process of the compressed air intake shutoff door and the regulating door of the expansion generator, the energy obtained by the rotor due to the rotational inertia is output and transferred in the form of electrical energy, the rotor speed is reduced, the occurrence of overspeed accidents is avoided, and the generated electrical energy can also be used as a backup power source.

Description

Technical Field

[0001] This invention relates to the field of overspeed control technology for load shedding, and in particular to a compressed air coupled chemical energy storage system and a method for controlling the speed during load shedding. Background Technology

[0002] Multi-stage expansion power generation systems are an important component of non-combustion compressed air energy storage systems. They contain multiple stages of expanders and heat exchangers, along with corresponding piping, resulting in a relatively large gas volume. During power generation, when a load shedding condition occurs, the generator outlet switch trips. Due to the hysteresis characteristics of signal transmission and control systems, the intake electric main valve will only begin to close after a certain delay time t1, and will not completely close and cut off the intake air until its own closing time t2. This causes the rotational inertia of the unit during load shedding to act on the rotor shared by the expander and generator, leading to an increase in the speed of both the expander and generator. Furthermore, due to the delayed closing of the intake electric main valve, residual pressurized gas in the expander, heat exchanger, and piping will continue to act on the rotor, further increasing the speed and potentially causing an overspeed accident. Summary of the Invention

[0003] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0004] In view of the problem that the increase in speed caused by the rotational inertia and the delayed closing of the intake electric main valve during the above-mentioned load shedding operation can lead to overspeed accidents, this invention is proposed.

[0005] Therefore, the purpose of this invention is to provide a compressed air coupled chemical energy storage system.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a compressed air coupled chemical energy storage system, including a power generation module that generates electricity by compressing air; a power transmission module that transmits the electricity generated by the power generation module to the power grid; and a load shedding module, in which the power transmission module is disconnected from the power generation module under load shedding conditions, the rotor speed increases due to the residual rotational inertia in the power generation module and the residual pressurized gas caused by the delayed closing of the intake electric main valve, and the load shedding module uses the residual kinetic energy to convert it into electrical energy for storage.

[0007] As a preferred embodiment of the compressed air coupled chemical energy storage system of the present invention, the power generation module includes a compressed air storage tank, an electric main valve for air intake located on the outlet main pipe of the compressed air storage tank, an air intake regulating valve connected to the outlet end of the electric main valve for air intake, a multi-stage expander connected to the air intake regulating valve, heat exchangers installed on the air intake pipes of the multi-stage expander, and a generator connected to the output end of the multi-stage expander.

[0008] As a preferred embodiment of the compressed air coupled chemical energy storage system of the present invention, the load shedding module further includes a current stabilizer connected to the generator power supply terminal, a QF5 circuit breaker is provided between the current stabilizer and the generator, a second transformer connected to the current stabilizer and an AC power distribution device connected to the second transformer, so that the unstable current and voltage generated by the generator module are stabilized under load shedding conditions, and then transmitted to the AC power distribution device for distribution.

[0009] As a preferred embodiment of the compressed air coupled chemical energy storage system of the present invention, the load shedding module further includes several electrochemical energy storage devices. The charging line of each electrochemical energy storage device is equipped with a fast-switching switch from QS1 to QSN, and the discharge line of each electrochemical energy storage device is equipped with a fast-switching switch from QS'1 to QS'N. The discharge line of each electrochemical energy storage device is connected to an electrochemical energy collection bus. Under the load shedding condition, when the generator outlet circuit breaker is opened, the electrochemical energy storage device is charged by load transfer.

[0010] As a preferred embodiment of the compressed air coupled chemical energy storage system of the present invention, the load shedding module further includes a QF3 circuit breaker connected to the electrochemical energy collection bus, a third transformer connected to the QF3 circuit breaker, a QF4 circuit breaker connected to the third transformer, and a tertiary load connected to the QF4 circuit breaker. After the electrochemical energy storage device stores energy, the energy is stepped down by the third transformer and supplied to various tertiary loads such as charging piles and emergency power supplies as backup power.

[0011] As a preferred embodiment of the compressed air coupled chemical energy storage system of the present invention, the power transmission module includes a QF1 circuit breaker connected to the generator power supply end, a first transformer connected to the QF1 circuit breaker, a QF2 circuit breaker connected to the first transformer, and a transmission bus connected to the QF2 circuit breaker.

[0012] As a preferred embodiment of the compressed air coupled chemical energy storage system of the present invention, wherein: the generator is connected to the drive shaft of at least one of the primary expanders, the total capacity of the electrochemical energy storage device is not less than 70% of the capacity of the compressed air energy storage system, and after the QF1 circuit breaker is closed, all fast-switching switches are disconnected, and the two are logically interlocked and cannot be put into operation at the same time.

[0013] The beneficial effects of the present invention are as follows: When encountering load shedding conditions during the power generation process, and the generator outlet circuit breaker is disconnected, the present invention charges the electrochemical energy storage device through load transfer. This allows the energy gained by the rotor due to rotational inertia during and after the compressed air intake shut-off valve and regulating valve are closed to be output and transferred in the form of electrical energy, thereby reducing the rotor speed and avoiding overspeed accidents. The generated electrical energy can also be used as a backup power source.

[0014] To address the issue of overspeed accidents caused by the increased rotor speed after load shedding, a load shedding speed control method is also provided, including the following steps:

[0015] Step S1: Obtain the grid connection switch status. When the grid connection switch is closed, determine whether the generator output power is greater than or equal to 50% of the rated power.

[0016] Step S2: When the generator output power is greater than or equal to 50% of the rated power and the grid connection switch is open, the intake electric main valve gradually begins to close, and the QS1 fast switch to the QSN fast switch automatically closes to start charging the electrochemical energy storage device.

[0017] Step S21: During the charging process, the intake electric main valve is fully closed. After the intake electric main valve is fully closed, the rotor speed is acquired until the rotor speed is less than or equal to 3000 r / min. When the rotor speed is less than or equal to 3000 r / min, the running time is acquired. When the running time is greater than 65s, the QS1 fast switch to the QSN fast switch is automatically disconnected.

[0018] Step S3: When the generator output power is less than 50% of the rated power and the grid connection switch is open, the intake electric main valve gradually begins to close, and the QS1 fast switch to the QS(N / 2) fast switch automatically closes to start charging the electrochemical energy storage device.

[0019] Step S31: During the charging process, the rotor speed and the fully closed state of the intake electric main valve are simultaneously acquired. If the rotor speed is less than or equal to 3000 r / min, the running time is acquired. When the running time is greater than 65s, the QS1 fast switch to the QS(N / 2) fast switch is automatically disconnected.

[0020] In step S32, if the intake electric main valve is fully closed, and the rotor speed still does not meet the requirement of less than or equal to 3000 r / min, then the QS(N / 2) fast switch to the QSN fast switch will close until the rotor speed is less than or equal to 3000 r / min. At this time, the running time is obtained. If the running time is greater than 65 seconds, the QS1 fast switch to the QSN fast switch will automatically disconnect.

[0021] In a preferred embodiment of the load shedding speed control method of the present invention, the total number N of fast-acting switches is even. During the load shedding process, the fast-acting switches can automatically close or open according to the opening / closing conditions, or be manually closed or opened after the conditions are met.

[0022] As a preferred embodiment of the load shedding speed control method of the present invention, the speed increase rate is calculated by the speed monitoring function of the control module, that is, the control module scans the data twice, and the difference between the two data is obtained by subtracting the interval time.

[0023] The beneficial effects of the present invention are as follows: Under load shedding conditions, the present invention can automatically determine and control the conduction of the energy storage device according to different rotor speeds. When the rotor speed drops to a level where overspeed accidents will not occur, the energy storage device is automatically disconnected. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of a compressed air coupled chemical energy storage system.

[0026] Figure 2 This is a logic control diagram for a fast-switching switch in a compressed air coupled chemical energy storage system.

[0027] Figure 3 This is another logic control diagram for a fast-switching switch in a compressed air coupled chemical energy storage system.

[0028] Figure 4 This is another logic control diagram for a fast-switching switch in a compressed air coupled chemical energy storage system.

[0029] Figure 5 This is a flowchart of a load shedding speed control method. Detailed Implementation

[0030] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0031] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0032] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0033] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0034] Example 1

[0035] Reference Figure 1 This is the first embodiment of the present invention. This embodiment provides a compressed air coupled chemical energy storage system, including a power generation module 100, which generates electricity by performing work with compressed air; a power transmission module 200, which transmits the electricity generated by the power generation module 100 to the power grid; and a load shedding module 300, which, under load shedding conditions, disconnects the power transmission module 200 from the power generation module 100. The rotor speed increases due to the residual rotational inertia in the power generation module 100 and the delayed closing of the intake electric main air valve 102 and the residual pressurized gas. The load shedding module 300 uses the residual kinetic energy to convert it into electrical energy for storage.

[0036] Specifically, the power generation module 100 is also equipped with a control module, which can monitor the expander speed and control various switches and valves. Based on the QF1 circuit breaker 201, the intake electric main valve 102, the expander speed ω, and the expander speed increase rate, the closing and opening conditions of each fast-switching switch are determined. The QF1 circuit breaker 201 controls whether the power transmission module 200 and the power generation module 100 are connected.

[0037] Furthermore, the power generation module 100 includes a compressed air storage tank 101, an electric intake main valve 102 disposed on the outlet main pipe of the compressed air storage tank 101, an intake regulating valve 103 connected to the outlet end of the electric intake main valve 102, a multi-stage expander 105 connected to the intake regulating valve 103, heat exchangers 104 installed on the intake pipe of the multi-stage expander 105, and a generator 106 connected to the output end of the multi-stage expander 105. The compressed air expands and depressurizes step by step through the multi-stage expander 105. The generator 106 is connected to the multi-stage expander 105 to generate electricity. The electric intake main valve 102 is used to control the opening and closing of the compressed air storage tank 101, and the intake regulating valve 103 adjusts the output flow of the compressed air storage tank 101.

[0038] Furthermore, the load shedding module 300 also includes a current stabilizer 301 connected to the power supply terminal of the generator 106. A QF5 circuit breaker 314 is also provided between the current stabilizer 301 and the generator 106. A second transformer 302 connected to the current stabilizer 301 and an AC power distribution device 303 connected to the second transformer 302 stabilize the unstable current and voltage generated by the generator module 100 under load shedding conditions, and then transmit it to the AC power distribution device 303 for distribution. Since the rotor speed shared by the generator 106 and the multi-stage expander 105 is constantly changing under load shedding conditions, the voltage and current of the electrical energy generated by the generator 106 are constantly changing. It is necessary to stabilize the electrical energy through the current stabilizer 301 and the second transformer 302 before transmitting it to the downstream energy storage.

[0039] Furthermore, the load shedding module 300 also includes several electrochemical energy storage devices 306. The charging lines of each electrochemical energy storage device 306 are equipped with QS1 fast-switching switches 304 to QSN fast-switching switches 305, and the discharging lines of each electrochemical energy storage device 306 are equipped with QS'1 fast-switching switches 307 to QS'N fast-switching switches 308. The discharging lines of each electrochemical energy storage device 306 are connected to an electrochemical energy collection bus 309. Under load shedding conditions, when the generator 106 output circuit breaker is open, the electrochemical energy storage devices 306 are charged through load transfer. The energy storage device 306 uses various devices capable of storing electricity, such as lead-acid batteries, sodium-sulfur batteries, flow batteries, and lithium-ion batteries. The AC power distribution device 303 distributes the electrical energy processed by the current stabilizer 301 and the second transformer 302 to each electrochemical energy storage device 306. The QS1 fast switch 304 to the QSN fast switch 305 control whether it is connected to the generator 106, and the QS'1 fast switch 307 to the QS'N fast switch 308 control whether it is connected to the electrochemical energy collection bus 309. The electrochemical energy collection bus 309 can transmit the electrical energy of each electrochemical energy storage device to other equipment for use.

[0040] Furthermore, the load shedding module 300 also includes a QF3 circuit breaker 310 connected to the electrochemical energy collection bus 309, a third transformer 311 connected to the QF3 circuit breaker 310, a QF4 circuit breaker 312 connected to the third transformer 311, and a tertiary load 313 connected to the QF4 circuit breaker 312. After the electrochemical energy storage device stores energy, the energy is stepped down by the third transformer 311 and then supplied to various tertiary loads 313, such as charging piles and emergency power supplies, as backup power. The QF3 circuit breaker 310 and the QF4 circuit breaker 312 control the connection between the tertiary load 313 and the electrochemical energy collection bus 309.

[0041] Furthermore, the power transmission module 200 includes a QF1 circuit breaker 201 connected to the power supply terminal of the generator 106, a first transformer 202 connected to the QF1 circuit breaker 201, a QF2 circuit breaker 203 connected to the first transformer 202, and a transmission bus 204 connected to the QF2 circuit breaker 203. The QF1 circuit breaker 201 controls the connection between the power transmission module 200 and the generator 106. When the QF1 circuit breaker 201 is closed, all fast-switching switches are open. When the QF1 circuit breaker 201 is open, the fast-switching switches can be closed.

[0042] Furthermore, the generator 106 is connected to the drive shaft of at least one of the expansion machines, and the total capacity of the electrochemical energy storage device 306 is not less than 70% of the capacity of the compressed air energy storage system. After the QF1 circuit breaker 201 is closed, all fast-switching switches are disconnected, and the two are logically interlocked and cannot be put into operation at the same time.

[0043] Operating Procedure: When the expander unit encounters a load shedding condition, the QF1 circuit breaker 201 at the generator 106 outlet trips. Due to the hysteresis characteristics of the transmission signal and control system, the intake electric main valve 102 will only begin to close after a certain delay time t1, and will only completely close and cut off the intake after its own closing time t2. This causes the rotational inertia of the unit during load shedding to act on the rotor shared by the multi-stage expander 105 and the generator 106, resulting in an increase in the speed of the multi-stage expander 105 and the generator 106. Due to the delayed closing of the intake electric main valve 102, the residual pressurized gas in the expander, heat exchanger 104, and pipelines will continue to act on the rotor, causing the speed to increase further. At this time, by performing logical judgments on the closing conditions of each fast-switching switch and controlling its operation, the generator 106 continues to generate electricity under the load shedding condition. The electrical energy is processed by the current stabilizer 301 and the second transformer 302 and then sent to each electrochemical energy storage device 306.

[0044] Example 2

[0045] Reference Figures 1-4This is the second embodiment of the present invention, which differs from the first embodiment in that it includes a compressed air storage tank 101, a heat exchanger 104, a series-connected multi-stage expander 105, multiple sets of electrochemical energy storage devices 306, and a generator 106. An intake electric main valve 102 and an intake regulating valve 103 are sequentially installed on the outlet main pipe of the compressed air storage tank 101. The intake regulating valve 103 is connected to the multi-stage expander 105. Each stage of the multi-stage expander 105 has a heat exchanger 104 installed on its intake pipe. The generator 106 is connected to the drive shaft of at least one stage expander. The charging line of the electrochemical energy storage device 306 is connected to the outlet line of the generator 106, and the connection and disconnection of the line are controlled by a QF1 circuit breaker 201 and a QS1 fast-switching switch 304 to QSN, respectively. The generator 106 generates electricity, which is then stepped up to the corresponding voltage level by a transformer and transmitted through the output bus 204. Multiple electrochemical energy storage devices 306 are controlled by QS'1 fast-switching switch 307 to QS'N fast-switching switch to switch their outgoing lines. After being collected by the busbar, they are connected to the transformer through QF3 circuit breaker 310. When providing load to the outside, the transformer steps down the voltage to meet various load requirements.

[0046] Specifically, the fast-acting switch can be opened immediately when the opening condition is met during the speed recovery process of the expander generator 106. The closing conditions of each fast-acting switch and its operation are determined according to the following conditions.

[0047] Furthermore, when the QF1 circuit breaker 201 is disconnected and the control module detects the disappearance of the signal indicating that the intake electric main valve 102 is in the open position, the fast-switching switch closes simultaneously. The number of fast-switching switches closed is determined based on the load before the expansion generator 106 sheds the load. If the load on the expansion generator 106 before shedding the load is ≤50% of the rated load, the fast-switching switches QS1 304 to QS(N / 2) automatically close. If the load on the expansion generator 106 before shedding the load is ≥50% of the rated load, the fast-switching switches QS1 304 to QSN automatically close. The disconnection condition is met after the rotor speed is ≤3000 r / min.

[0048] Furthermore, the speed monitoring module continuously monitors the real-time speed and speed increase rate. The speed increase rate is determined by...

[0049] Calculate using Equation 1:

[0050]

[0051] in,

[0052] Δω, the rate of increase in rotational speed, in m / s²;

[0053] ω1, real-time rotor speed, in m / s;

[0054] ω2, the rotor speed at the previous moment, in m / s;

[0055] t, the scanning time of the speed monitoring module, in seconds. In this embodiment, it is the interval between two data scans by the speed monitoring module.

[0056] When the intake electric main valve 102 is detected to be closed, if the speed monitoring of the control module detects that the rotor speed ω≥3060r / min, or ω≥3030r / min and Δω≥3.34r / s2, all fast-acting switches will be closed and operated until the speed is ≤3000r / min, at which point the fast-acting switches will be ready to disconnect.

[0057] Furthermore, during the load shedding process, the fast-acting switch can automatically close or open depending on whether the opening / closing conditions are met, or it can be manually closed or opened after the conditions are met.

[0058] The rest of the structure is the same as in Example 1.

[0059] Operation process: High-pressure air is stored in an air storage tank. The outlet flow rate is regulated by the intake electric main valve 102 and the intake regulating valve 103. It enters the multi-stage heat exchanger 104 for heat exchange. After heat exchange, the high-pressure air enters the multi-stage expander 105 for expansion, driving the generator 106 to generate electricity. At this time, the charging circuit switches from QS1 to QSN of the electrochemical energy storage device 306 are open, and the energy storage device is not in the charging state. The circuit breakers QF3 310, QF4 312, and the step-down transformer select whether to close and put into operation according to the energy storage status and condition of the electrochemical energy storage device 306.

[0060] Example 3

[0061] Reference Figure 5 This is the third embodiment of the present invention. Unlike the previous embodiments, this embodiment also provides a method for controlling the speed of load shedding, comprising the following steps:

[0062] Step S1: Obtain the grid connection switch status. When the grid connection switch is closed, determine whether the output power of generator 106 is greater than or equal to 50% of the rated power.

[0063] Step S2: When the output power of generator 106 is greater than or equal to 50% of the rated power and the grid connection switch is open, the intake electric main valve 102 gradually begins to close, and the QS1 fast switch 304 to the QSN fast switch 305 automatically close, starting to charge the electrochemical energy storage device.

[0064] Step S21: During the charging process, the fully closed state of the intake electric main valve 102 is obtained. After the intake electric main valve 102 is fully closed, the rotor speed is obtained until the rotor speed is less than or equal to 3000 r / min. When the rotor speed is less than or equal to 3000 r / min, the running time is obtained. When the running time is greater than 65s, the QS1 fast switch 304 to the QSN fast switch 305 are automatically disconnected.

[0065] Step S3: When the output power of generator 106 is less than 50% of the rated power and the grid connection switch is open, the intake electric main valve 102 gradually begins to close, and the QS1 fast switch 304 to the QS(N / 2) fast switch automatically closes to start charging the electrochemical energy storage device.

[0066] Step S31: During the charging process, the rotor speed and the fully closed state of the intake electric main valve 102 are simultaneously acquired. If the rotor speed is less than or equal to 3000 r / min, the running time is acquired. When the running time is greater than 65s, the QS1 fast switch 304 to the QSN fast switch 305 are automatically disconnected.

[0067] In step S32, if the intake electric main valve 102 is fully closed, and the rotor speed still does not meet the requirement of less than or equal to 3000 r / min, then the QS(N / 2) fast switch to the QSN fast switch 305 closes until the rotor speed is less than or equal to 3000 r / min. At this time, the running time is obtained. If the running time is greater than 65s, the QS1 fast switch 304 to the QSN fast switch 305 automatically disconnects.

[0068] Specifically, the total number N of fast-acting switches is an even number. During the load shedding process, the fast-acting switches can automatically close or open according to the opening / closing conditions, or be manually closed or opened after the conditions are met.

[0069] Furthermore, the rate of increase in rotational speed is calculated using the rotational speed monitoring function of the control module. That is, the control module scans the data twice, and the difference between the two data points minus the time interval is obtained.

[0070] The rest of the structure is the same as in Example 2.

[0071] Operation process: During startup, the control system of generator 106 detects in real time whether the output power of generator 106 is ≥50% of the rated power. When the grid connection switch is disconnected, the intake electric main valve 102 begins to close.

[0072] If the output power of generator 106 is ≥50% of the rated power, all fast-switching switches will automatically close. Generator 106 will continue to generate electricity under the action of rotational inertia and the remaining compressed air in the expander. The generated electrical energy is stored in the electrochemical energy storage device 306. As time goes by, the intake electric main valve 102 will be completely closed during the charging process. At this time, the rotor speed is detected. If the rotor speed is >3000 r / min, the detection will continue until the rotor speed is ≤3000 r / min. At this time, the running time is judged. If the running time is >65s, the fast-switching switch will be disconnected. If the running time is insufficient, the operation will continue until the running time is >65s.

[0073] If the output power of generator 106 is less than 50% of the rated power, first close half of the quick-switch until the intake electric main valve 102 is fully closed. At this time, the rotor speed is detected. If the speed is ≥3060 r / min, the other half of the quick-switch is also closed until the rotor speed is ≤3000 r / min. At this time, the running time is detected. If the running time is >65s, the quick-switch is opened. If the rotor speed is <3060 r / min but ≥3030 r / min when the intake electric main valve 102 is fully closed, and the rotor speed increase rate is ≥3.34 r / s2, the other half of the quick-switch is closed until the rotor speed is ≤3000 r / min. At this time, the running time is detected. If the running time is >65s, the quick-switch is opened.

[0074] It is important to note that the constructions and arrangements of this application shown in several different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible (e.g., changes in the size, dimensions, structure, shape, and proportions of various elements, as well as parameter values ​​(e.g., temperature, pressure, etc.), mounting arrangements, use of materials, color, orientation, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in this application). For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of elements may be inverted or otherwise altered, and the nature or number or position of discrete elements may be changed or altered. Therefore, all such modifications are intended to be included within the scope of the invention. The order or sequence of any process or method steps may be changed or rearranged according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and not only structurally equivalent but also equivalent in structure. Other substitutions, modifications, alterations, and omissions may be made in the design, operation, and arrangement of the exemplary embodiments without departing from the scope of the invention. Therefore, the present invention is not limited to the specific embodiments, but extends to various modifications that still fall within the scope of the appended claims.

[0075] Furthermore, in order to provide a concise description of exemplary embodiments, not all features of actual embodiments (i.e., those features that are not relevant to the best mode of carrying out the invention as currently considered, or those features that are not relevant to implementing the invention) may be omitted.

[0076] It should be understood that numerous specific implementation decisions can be made during the development of any practical implementation, such as in any engineering or design project. Such development efforts may be complex and time-consuming, but for those skilled in the art who benefit from this disclosure, the development effort will be a routine work of design, manufacturing, and production without requiring much experimentation.

[0077] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for controlling speed during load shedding, comprising the following steps: Step S1: Obtain the grid connection switch status. When the grid connection switch is closed, determine whether the generator output power is greater than or equal to 50% of the rated power. Step S2: When the generator output power is greater than or equal to 50% of the rated power and the grid connection switch is open, the intake electric main valve gradually begins to close, and the QS1 fast switch to the QSN fast switch automatically closes to start charging the electrochemical energy storage device. Step S21: During the charging process, the intake electric main valve is fully closed. After the intake electric main valve is fully closed, the rotor speed is acquired until the rotor speed is less than or equal to 3000 r / min. When the rotor speed is less than or equal to 3000 r / min, the running time is acquired. When the running time is greater than 65s, the QS1 fast switch to the QSN fast switch is automatically disconnected. Step S3: When the generator output power is less than 50% of the rated power and the grid connection switch is open, the intake electric main valve gradually begins to close, and the QS1 fast switch to the QS(N / 2) fast switch automatically closes to start charging the electrochemical energy storage device. Step S31: During the charging process, the rotor speed and the fully closed state of the intake electric main valve are simultaneously acquired. If the rotor speed is less than or equal to 3000 r / min, the running time is acquired. When the running time is greater than 65s, the QS1 fast switch to the QSN fast switch is automatically disconnected. In step S32, if the intake electric main valve is fully closed in step 31, and the rotor speed still does not meet the requirement of less than or equal to 3000 r / min, then the QS (N / 2) fast switch to the QSN fast switch will be closed until the rotor speed is less than or equal to 3000 r / min. At this time, the running time is obtained. If the running time is greater than 65 seconds, the QS1 fast switch to the QSN fast switch will be automatically disconnected. The load shedding speed control method is applied to a compressed air coupled chemical energy storage system, which includes... A power generation module (100) generates electricity by compressing air; a power transmission module (200) transmits the electricity generated by the power generation module (100) to the power grid; characterized in that it further includes, In the load shedding module (300), the power transmission module (200) is disconnected from the power generation module (100) under load shedding conditions. The rotor speed increases due to the residual rotational inertia in the power generation module (100) and the residual pressurized gas caused by the delayed closing of the intake electric main valve. The load shedding module (300) uses the residual kinetic energy to convert it into electrical energy for storage. The power generation module (100) includes a compressed air storage tank (101), an electric main intake valve (102) located on the outlet main pipe of the compressed air storage tank (101), an intake regulating valve (103) connected to the outlet end of the electric main intake valve (102), a multi-stage expander (105) connected to the intake regulating valve (103), heat exchangers (104) installed on the intake pipe of the multi-stage expander (105), and a generator (106) connected to the output end of the multi-stage expander (105). The load shedding module (300) also includes a current stabilizer (301) connected to the power supply terminal of the generator (106). A QF5 circuit breaker (314) is also provided between the current stabilizer (301) and the generator (106). A second transformer (302) connected to the current stabilizer (301) and an AC power distribution device (303) connected to the second transformer (302) stabilize the unstable current and voltage generated by the generator module (100) under load shedding conditions, and then transmit them to the AC power distribution device (303) for distribution. The load shedding module (300) also includes several electrochemical energy storage devices (306). The charging lines of each electrochemical energy storage device (306) are equipped with QS1 fast-switching switches (304) to QSN fast-switching switches (305), and the discharge lines of each electrochemical energy storage device (306) are equipped with QS'1 fast-switching switches (307) to QS'N fast-switching switches (308). The discharge lines of each electrochemical energy storage device (306) are connected to an electrochemical energy collection bus (309). Under the load shedding condition, when the generator (106) outlet circuit breaker is opened, the electrochemical energy storage device (306) is charged by load transfer.

2. The load shedding speed control method as described in claim 1, characterized in that: The load shedding module (300) also includes a QF3 circuit breaker (310) connected to the electrochemical energy collection bus (309), a third transformer (311) connected to the QF3 circuit breaker (310), a QF4 circuit breaker (312) connected to the third transformer (311), and a third-level load (313) connected to the QF4 circuit breaker (312). After the electrochemical energy storage device stores energy, the energy is stepped down by the third transformer (311) and then supplied to the third-level load (313) as a backup power source.

3. The load shedding speed control method as described in claim 2, characterized in that: The power transmission module (200) includes a QF1 circuit breaker (201) connected to the power supply end of the generator (106), a first transformer (202) connected to the QF1 circuit breaker (201), a QF2 circuit breaker (203) connected to the first transformer (202), and a transmission bus (204) connected to the QF2 circuit breaker (203).

4. The load shedding speed control method as described in claim 3, characterized in that: The generator (106) is connected to the drive shaft of at least one of the expansion machines. The total capacity of the electrochemical energy storage device (306) is not less than 70% of the capacity of the compressed air energy storage system. After the QF1 circuit breaker (201) is closed, all fast-switching switches are disconnected, and the two are logically interlocked and cannot be put into operation at the same time.

5. The load shedding speed control method as described in claim 4, characterized in that: The total number N of fast-acting switches is an even number. During the load shedding process, the fast-acting switches can automatically close or open according to the opening / closing conditions, or be manually closed or opened after the conditions are met.

6. The load shedding speed control method as described in claim 5, characterized in that: The rate of increase in rotational speed is calculated using the speed monitoring function of the control module. This involves the control module scanning the data twice, and the difference between the two data points minus the time interval.

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